Exploiting Conserved Quorum Sensing Signals in Streptococcus mutans and Streptococcus pneumoniae.

Bacterial species of the genera are considered either commensal bacteria or potential pathogens, according to their metabolic evolution and production of quorum sensing (QS)-controlled virulence factors. in particular, has become one of the best-studied examples of bacteria that are able to get along or cheat commensal species, even of the same genera. and share homolog QS pathways and a competence stimulating peptide (CSP) for regulating bacteriocin production. Intriguingly, the abundance of and alternates in complex microbial communities, thus opening the role for the fratricide communication of homolog QS systems. Since the inhibition of the QS has been proposed in treating bacterial infections, in this study, we designed and synthesized analogs of CSP with precise residual modifications. We reported that CSP analogs reduced the expression of genes involved in the QS of and biofilm formation without affecting bacterial growth. The CSP analogs inhibited bacteriocin production in as reported by co-cultures with commensal bacteria of the oral cavity. The peptide CSP1AA, bearing substitutions in the residues involved in QS receptor recognition and activation, reported the most significant quorum-quenching activities. Our findings provide new insights into specific chemical drivers in the CSP sequences controlling the interconnection between and . We think that the results reported in this study open the way for new therapeutic interventions in controlling the virulence factors in complex microbial communities such as the oral microbiota.